Lapping apparatus



March 1940- D. A. WALLACE LAPPING APPARATUS Filed Jan. 30, 1957 EL #0 Wm M [W A A W L V I m Q\ oth r no. 26, ion 2,195,051

UNITED STATES PATENT OFFICE LAPPI NG APPARATUS David A. Wallace, Detroit, Mich., assignor to Chrysler Corporation, Highland Park, Mich, a corporation of Delaware Application January 30, 1937, Serial No. 123,118

'1 Claims. (Cl. 5164) This invention relates to improved apparatus ed with a dead spindle l6 which is in axial alignfor lapping cylindrical members. ment with the live spindle l4.

Particularly, the invention pertains to improve- Mounted on the base structure adjacent ments in the method of and apparatus for 1942- the reciprocable carriage II and between the ping external cylindrical surfaces of plug gauges, live and dead spindles l4 and I6, respectively, 5

shafts and the like. is a tool fixture ll which is stationary with re- .One of the main objects of the invention is spect to'the reciprocating movement of the car-' to provide lapping apparatus by which the work riage II. The fixture l1 includes an arm l8 on can be simultaneously rotated with respect to a the upper end of which is provided the lapping 1o fixed axis and subjected to one stage of reciprot l s p t h ed structur n al y desi 10 catory movement during application thereto of nated by t nu l 9, comprising fixed a a lapping element which is undergoing reciproremovable plate members and 2|, respectivecation of an entirely difierent order. 13?, which are detachably connected tog t by Another object of the invention is to provide ws S y engaged between the Plates l5 apparatus of this character by which the lapping 2B and 2 s a shank 23 O a y p 15 element may be reciprocated at a speed of a suba llustrated in Fig. 2.. The shank 23 stantially vibratory order while applied to a piece has fl es 011 its extremity which are e of work which is at the same time reciprocating ediate in ooves 25 fo ed i t e pla e at a lower speed and throughout a longer course The grOOVes 25 0f the p t 7| serve to co fi a and rotating about an axis extending substanth m v m nt f t yok shaped m m r 24 2o tially parallel to the courses of said reciprocatory to a Course Substantially Parallel t e axis of movements. rotation of the live spindle and the work 26. A further object of the invention is to pro- Pivotally m unt d on th y k 4 b tween th vide a lapping operation of this character by arms thereof is a l p ement ca 1 25 which the machine formed grooves and ridges of Comprising a Split ring having outwardly 25 the surface operated upon can be removed withtending lugs 28 y which the ring y be 0 out producing lapping formed surface scratches. traeted in Order to pp y pp ents An additional object of the invention is the mounted in the c e 21 t0 e Wo k 6. T e provision of lapping apparatus by which is prolapping nt carrier 27 is Pivotally supported duced relative movements between the piece of y P 29 Which are received in apertures rmed 30 work and the lapping element that is the result In the outer e po of t e a m 6' of the of a plurality of difierent component movements 'y e in excess of two components, of which each Mounted on the head I9 of the fixture arm l8 component is confined to one characteristic of is an electric meter 39, other b e driving the contour desired in order to facilitate bringmeans, having a s aft 3| t di t u a 35 ing of the work to a predetermined contour withpassage 32 in t e head 9 a d through registerin a high degree of accuracy. ing openings in the plates 211 and 2|. The left An illustrative embodiment of the invention extremity of the cross h portion 23 f he is shown in the accompanying drawing, in which: 24, as mg in is Provided with 40 1 is a fragmentary side elevational View a recess 33 which is elongated and which extends 40 f a lapping machine embodying the invention transversely of the axis of the shaft 3|. The

Fig. 2 is a fragmenta ri ht end elevation 1 right extremityqf the has an eccen" I View of the apparatus g i in 1' trically located pm 34 which is received in the Fig. 3'is a fragmentary vertical sectional view {3, 2 g z gggg g zgg g s 222 25 2 2: i gig z z'g if f ig t t d tween the opposite side walls ,of the recess 33 th drawm the m f d l m e m and thus during rotation of the shaft an by the e t ptove g apparatus motor 30, the yoke 24 and lapping elements 21 ase 5 we on which is are reciprocated in the direction 01' the axis of ria e y u t d on t e carriage ll erated at a speed such that from 900 to 2300 is a mot r Other a l driving means. reciprocations per minute of the. lapping elements having a sh Provided Wlth & l ve spindle ll. 21 will be produced. The length of the stroke A dead spindle fixture I5 is longitudinally adof the reciprocatory movement of the yoke 24 55 justably mounted on the carriage H and providand lapping elements 21' produced by the motor 55" 0 ably mounted a longitudinally reciprocable carthe work 5 otor '30 is preferably op- 30 is relatively short but the reciprocations occur at a comparatively high frequency.

The work 26 is reciprocated relative to the lapping tool fixture l1 and lapping elements 21' by driving mechanism, which drives a shaft 36 journalled in suitable bearings carried by the base structure II] of the lapping machine and operatively connected with a driving member (not shown). Mounted on the shaft 36 is a crank disc 31 on which the right end of a link 38 is eccentrically pivoted at 39. The left end of the link 38 is pivotally attached at 40 to a bracket 4| rigidly secured to the lower side of the shiftable carriage ll. During rotation of the crank disc 31 by the shaft 36 the carriage ll, motor l2, and dead spindle support l5, together with the work 26, are reciprocated in the direction of the axis of the work, preferably at a speed of from 100 reciprocations to 300 reciprostages of relative reciprocatory movement of the work and lapping stones, preferably at from 100 to 300 R. P. M. but naturally these rotative and reciprocatory speeds may be varied in accordance with the dimensions and nature of the work.

With the foregoing apparatus, relative movement is produced between the lapping elements of the work which is a resultant ofa plurality of component movements and therefore repeated application of any localized hard spots or grains of the lapping elements to the same area of the work is efiectively guarded against. The relative reciprocatory movements of the lapping elements and the work at comparatively different speeds throughout different lengths of strokes assures that the surface operated upon will be brought to a truly cylindrically contour of a predetermined diameter. The pressure applied by the lapping element 21' on the work may be predetermined by adjustment of the set screw 42 and may be limited by inserting a suitable shim 43 between the outwardly extending lugs 28 of the lapping element carrier.

The relative movement produced between the lapping element and the work by the foregoing A apparatus and method therefore assures bringing of the surface to a high degree of smoothness while removing all machine formed ridges and without scratching the surface by repeatedly applying localized hard areas of the lapping element to the same area of the work. Thecombined relative rotary and two stage reciprocatory movements of the work and lapping elements facilitate the bringing of the external surface of the work to true cylindrical contour.

Although but one specific embodiment of the invention is herein shown and described, it will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of my invention. 4

What I claim is:

1. Lapping apparatus comprising a support, a carriage shiftably mounted on said support, means on said carriage for rotatably supporting and drivingly rotating a piece of work about an axis substantially parallel to i. the direction of shifting movement of said carriage, a tool fixture mounted on said support, a lapping tool on said fixture, including a main body portion and a lapping element engageable with said work and shiftably mounted on said main body portion for reciprocatory movement in a course substantially parallel to said axis, and means for drivingly reciprocating said lapping element relative to said bodyportion and for drivingly reciprocating said carriage respectively at respectively different speeds and throughout correspondingly different lengths of stroke, said last mentioned means being so constructed and arranged as to reciprocate said carriage at a slower speed than that of said lapping element but throughout a number of strokes substantially corresponding to the number of rotations of said work per unit of time.

2. Lapping apparatus comprising a support, a carriage shiftably mounted on said support, means on said carriage for rotatably supporting and drivingly rotating apiece of work about an axis substantially parallel to the direction of shifting movement of said carriage, a tool fixture mounted on said support including a lapping element engageable with said work and shiftably mounted on said fixture for reciprocatory movement in a course substantially parallel to said axis, means for drivingly reciprocating said lapping element throughout a relatively 3. Lapping apparatus comprising a support,

a carriage shiftably mounted on said support, means on said carriage for rotatably supporting and drivingly rotatinga piece of work about an axis substantially parallel to the direction of shifting movement of said carriage, a tool fixture on said support, a lapping member support shiftably mounted on said fixture for reciprocation in a course substalfigially parallel to said axis, and a lapping me er pivotally mounted on said holder about a pivotal axis substantially normal to the axis of rotation of said work and having lapping elements engageable with said work, and means for drivingly reciprocating said work and said lapping elements simultaneously throughout respectively different lengths of stroke and at correspondingly difierent speeds, said means being so constructed and arranged as to reciprocate said lapping element at a speed of from 900 to 2300 reciprocations per minute and to reciprocate said work at a speed of from to 300 reciprocations per minute.

4. Lapping apparatus comprising a support, a carriage reciprocably mounted on said support, means on said carriage for rotatably supporting and drivingly rotating a piece of work, means for confining the reciprocatory movement of said carriage to a course substantially parallel to the rotative axis of said work, 'a tool fixture on said support, a lapping tool on said fixture including a main body portion and a lapping element engageable with said work and shiftably mounted on said main body portion for reciprocatory movement in a course substantially parallel to means on said carriage for rotatably supporting and drivingly rotating a piece of work, means for confining the reciprocating movement of saidcarriage to a course substantially parallel to the rotative axis of said work, a tool fixture on said support, a lapping tool on said fixture including a main body portion and a. lapping element engageable with said work and shiftably mounted on said main body portion for reciprocatory movement in a course substantially parallel to said axis, and means operable during rotation of face of a piece of work to true cylindrical contour comprising a support, work holding mechanism on said support including means for drivingly rotating work about an axis concentric with said surface, a lapping tool on said support including a main body portion and a lapping element engageable with said surfaces and shiftably mounted on said main body portion for reciprocatory movement in a course substantially parallel to said axis, said tool and said work being bodily relatively reciprocable with respect to each other in a course substantially parallel to said axis, and means for drivingly reciprocating said lapping element relative to said main body portion of said tool and for drivingly producing relative bodily reciprocation of said tool and work in said respective courses during rotation of said work.

'7. Finishing apparatus comprising a base structure, a pair of supports on said base structure, one being relatively linearly shiftable with respect to the other in a predetermined course, means on one of said supports for rotatively mounting and drivingly rotating a piece of work with respect to an axis extending substantially parallel to said course, a finishing tool on the other support including a main body portion and an abrading element engageable with said work and shiftably mounted on said main body portion for reciprocatory movement in a course substantially parallel to said courses and axis, and means for drivingly producing relative reciprocatory movements between said supports and for drivingly reciprocating said abrading element 25 relative to said body portion respectively at different speeds and in their said respective courses of reciprocatory movements.

DAVID A. WALLACE. 

